Robert T. Paine

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Alternative Titles:
Robert T. Paine, Robert Treat Paine III

Robert T. Paine, (Robert Treat Paine III), American ecologist (born April 13, 1933, Cambridge, Mass.—died June 13, 2016, Seattle, Wash.), was an icon in the field of ecology and the originator of the keystone specieshypothesis, which posited that some species (typically large predators) have a disproportionately large effect on the biological communities in which they occur. Paine received a B.S. (1954) from Harvard University and earned a Ph.D. in zoology (1961)
from the University of Michigan before joining (1962) the University of Washington as an assistant professor in the department of zoology. Paine unveiled (1969) his keystone species hypothesis after researching the ochre sea star (Pisaster ochraceus), a predatory species in the tidal pool communities on Tatoosh Island in the Pacific Northwest. After removing all of the sea stars from the tidal pool, he discovered that the mussel population rose dramatically. The mussels covered the rocky surfaces of the tidal pool to the detriment of other tidal pool denizens (limpets, barnacles, and sponges) and thus changed the structure of the tidal ecosystem. He noticed similar patterns in kelp forest ecosystems when sea otter populations declined; the population of their prey, sea urchins, grew large, consuming enough kelp to drive away other animals that would normally feed on that seaweed. Paine’s groundbreaking keystone species concept, which was later clarified to describe the impact of strong single-species relationships that were out of proportion with the species’ biomass in the ecosystem, became an important factor in conservation; many ecologists used his model to guide their decisions on which habitats and ecosystems to protect to maximize biodiversity. Paine was presented with the MacArthur Award from the Ecological Society of America in 1983 and the International Cosmos Prize in 2013.